Manufacture of steel.



W. R. WALKER.

MANUFACTURE OF STEEL.

APPLICATION I'ILED APR. 28,1911.

Patented Aug. 13, 1912.

3 SHEETSSHBET 1.

i-Q-i F5 I I a mvmR 44 v YMKDTTORNEV W. R. WALKER. MANUFACTURE OPSTEEL.

APPLICATION FILED APR.28,1911.

1,035,280, Patented Aug. 13, 1912,

3 SHEETS-SHEET 2.

w WWII/KNOB 7W MZ ATTORNEY W. R. WALKER.

MANUFACTURE OF STEEL.

APPLICATION FILED APR.28,1911.

1,035,280, Patented Aug. 13,1912.

3 SHEETSSHEET 3.

I II if i $3 Q WILLIAM R. WALKER, 0F YORK, N. Y.

MANUFACTU'RE OF STEEL.

Specification of Letters Patent.

Application filed April 28,

Patented Aug. 13, 1912. 19-11. Serial No. 623,908.

furnaces in combination with combustion furnaces, such as an open hearth furnace or Bessemer converters, for making and finishing steel or the like.

The object of the invention is to reduce the cost of the steel; to make steel of a more uniform carbon-content even-in the usually diflicult caseoflow-carbon steel; and to effect a nearly complete removal of slag; especially what may be called microscopic slag, disseminated through the bath of molten steel coming from the electric furnace.

A further object is to shorten the period for retaining the steel in the electric finishing furnace, andgivebetter dissemination of the additions.

Incarrying out the first named objects, I employ. a mixer, preferably in the form of a mixing ladle Wlillh an acid lining, which may or may not be heated by electrodes, or otherwise, this mixer receiving the steel from several electric furnaces and preferably traveling in front of them. A constant pool of steel is kept in this steel-mixer, so

that as themetal istapped from an electric furnace into the pool it is mixed thereinwith other steel;and1 portions of the pool are taken from the-mixer as desired, to teeminto the molds, the poolbeing constantly maintained inthe mixer. In this mixer also small additions may be made, such for example as carbon, to bring the metal up tothe desired content. I also prefer to employ a mixer or mixers between the con-= .verters or open hearth: furnaces and the electric furnaces, so as to secure more uniform metal for supplying to the electric furnaces. These mixers feeding to-the-electric furnaces are preferably lined with basic or neutral material so-that-a certain degree of dephosphorizingmay be carried: out therein with a suitable slag (and incidentally desulfurizing').

By the use of this systemI am-enabled to:

keep the electric furnaces in substantially in use it cools rapidly and there is no convenient means for keeping it hot. The

maintaining of a continuous supply of molten metal reduces to a minimum the time during which the electric furnace is permitted to cool. The providing of the pool in the final mixer gives a more uniform carbon-content in the finished steel fed into the molds, owing to the mixing action; while the providing of the constant pool gives a further refining action by more thoroughly disseminating the additions and also by allowing the slag to separate more thoroughly from the steel and rise to the surface; What I have termed microscopic slag is thus more completely eliminated from the steel, such slag tending to impair the quality of the steel and interfere with the after operations on the ingots. The. use of this pool following the electric finishing treatment also enables me to shorten thetime for treatment in' the electric furnaces, since the heat of the steel coming from the furnaces is sohigh that the refining continue in the mixer, and the metal may be tapped 0r poured from the electric furnace at anearlier stage than heretofore. The treatment in the electric furnace is the most expensive of the several steps employed.

By carrying on the last degree of refinement in the mixing. ladle, the time of using the electric furnace is curtailed for each melt, or the product is carried to a higher degree of refinement. This finishing mixer also serves to reduce the temperature of the electric steel to a better temperature for teeming. into the ingot molds.

As to further objects of my invention,

I- propose to use an acid lined electric furnace, which is cheaper both in first co'st and in cost of-repairs, and gives a greater output in a: given time than a basic lined elec tric'furnace, and can therefore be worked with lower costs of labor andof current ?per ton of product. With such an electricifurnace I propose toemploy a basic lined 5 converter in-which the molten. pigis dephosiphorized; and in which the additional cost *overan. acid lined converteris comparatively small ;this being more than over come by the saving in the cost of operating the. electric furnace; Moreover, in this sys-' tem the converter may be used to give merely a roughing-down operation; the

metal not being as completely blown or carefully finished 'asin previous basicconverter Work. Ae-Qtiauxite or other neutral lining may be substituted for the acid lining of the electric furnace in special cases.

' It will-be understood that my system and process may be employed,- however, with basic lined electric furnaces receiving metal from converters or open hearth furnaces, within the scope of my broader claims, and that the acid electric furnace may be employed with the basic converter with or without the other steps of the process specifically described.

The stationary mixers described, as well as themixing ladles, may be heated electrically or otherwise.

The accompanying drawings illustrate a suitable arrangement of apparatusfor carrying out the invention.

Figure 1 is a plan partly in section of a complete plant for carrying out the operations from the Bessemer converters to the ingot molds, omitting'certain ladles, charging apparatus and slag cars. Fig.2 is a transverse View of theplant shown in Fig. 1

showing the various ladles and appurtenances. Figs. 3 and 4 are respectively a vertical section and a cross section on the line 4.-4 showing an electrically heated mixing ladle.

Referring first to Fig. 1 as showing the preferred arrangement ofthe apparatus of the plant, A and B are Bessemer converters of say thirteen (13) tons capacity each and arranged in a line at one side of the plant.

' In line adjacent to these converters are two mixers C and D. These may be tilting vessels heated by gas or electricity or otherwise and having a capacity of onehundred and fifty (150) tons each. In the next line isa row of electric furnaces in two groups indicated at E and F respectively and these may pac'ity each.=

The converters, mixers and electric furnaces above referred to are fixed-except for the tilting movements necessary in charging be'of about twenty-five (25) tons ca-- tions are stands K carrying casting ladles L of say twenty-five (25) tons capacity, so

that the molds can be run under these .casting ladles and then filled therefrom.

The process which I prefer in detail involves the use of a basic converter and mixer and an acid electric furnace. Such process, however, is of especial value in using high phosphorous pig, and such a large plant as I have designed above 'can be adapted to use pig which is either high or low in phosphorus by merely modifying the linings of the vessels (and, of course, altering the character of the additions and the slags correspondingly). For example, the converter A may be acid lined, the converter B basic lined; and'the electric furnaces'E may be basic lined, while the furnaces F are acid lined. The mixers O and D would ordinarily be lined alike with basic or neutral lining as the only substantial change therein is a dephosphorization (with a slight incidental desulfurization). The ladles may be acid as usual since there are no chemical operatlons earned on thereln or at least none which involve a consideration of the character of the lining. With the various vessels of the character described the plant can handle non-phosphoric pig most readily in the converter A and furnaces E; and phosphoric pig most readily in the converter B and furnaces F; ortwo series of operations can be carried on simultaneously using the converter A, mixer C and the four furnaces E in one group, and the converter B, mixer D and four furnaces F in a secondgroup, using the mixing ladles G and H for p any desired one or both of the furnace groups.

Fig. 2 illustrates the mode of transferring the metal from one apparatus to the next. This figure shows at M a ladle carried on 'a track and serving'to bring molten pig iron from the blast furnace or. cupola. The iron is poured from the ladle M into one 'endof an iron mixer N of the tilting type, andfrom the opposite end of this mixer the metal is poured into'a ladle O traveling on an elevated track in front of the converters and the iron mixer N, the latter being at one end of the lineof the converters. The ladles O are then used to charge the converters and the latter'are discharged into a second line of ladles P carried on a track running on a lower; level in front of the line of converters. 'From the ladles P the steel is poured into the stationary steel mixers at one side, these being of'the tilting ty e so that the metal is poured therefrom at t "e opposite side into. a ladle Q carried by a traveling crane R which lifts it and conveys it over to a position in the rear of the electric furnaces where itis tilted to pour its contents into the furnace at the rear, the latter be- 1% ing'also of the. tilting variety and the-steel metal into the ingot molds T which are passed in succession under the stand .on-

be ng poured'throug'h a spout at the front' into the large mix1ng ladle G; which is handled by a traveling crane S to raise itand shift it laterally to a point above the" 'small ladles L into which parts of-itscontents-are poured from time to time, the casting ladles L being then used to teem the which the casting ladles are mounted. In connection with the electric furnaces there is also mounted at the rear of .the line a charging a paratus U traveling upon a track paral el with the furnaces and adapted to be used for charging slag-forming materials, lime, ore, scrap, cold metal and any desired additions to the bath in the electric furnace. The charging apparatus U- works.

in connection with cars V-running on a parallel track and carrying thematerials to, be charged. At a lower level and between the cars V and the rear end of the furnace there are provided tracks for running slag cars W into the mixing ladle.

up to the furnaces so that the latter can be first tilted backward to pour off the slag before being tilted forwar The mixing ladlesG, Hor the casti'ng 'ladls L, or both, may be covered and provided with electrodes in the manner shown in Figs. 3 and 4. The vessel L for example .has a nozzle X in the bottom through which the contents are discharged, the flow being regulated by a stopper Y consisting of a steel'rod inclosed in hollow bricks and connected to alever Z on the outside by which it is manipulated. The side of the vesselthrough which the stopper Y passes is open" at .thetop. .The diaphragm 2, however, in connection with a roof?) incloses theremaining portion of the surface of the metal and --the electrodes 4 are let down through the cover 3 and'a current*caused to pass from one electrode through the metal to the other accordi'ngto the principle of the Heroultarc furnace, suiiicient current being supplied-to provide the desired quantity of heat.

Theadvantages of my invention will be.

apparent to those skilled in'this art. The cost of producin electrically finished steel is greatly reduce the carbon content of the finished steel ismade more uniform; the metal is morecompletely refined and the slag eliminated to a greater extent than heretofore, while the time of retaining the to pour the steel the steps of the process and sub-pro' 'c esses,-

Without departing r m my invention.

1'. In the manufacture'of steel the which consists in subjecting phosphoric iron to a roughing-down blowing operation in basic converters, transferring-.. the metal: I

therefrom to amixer, completing the de-,. sired dephosphorizing infl said mixer and '5" ring metal from the mrxerto an-ac1d-.elecmaintaining. a supply therein. and transfertric furnace and refining'it therein.

2. In the manufacture of steel the method which consistsin blowing'iron in basic -converters, transferring ittherefro to anonacid mixer, maintaining a supply in said mixer, transferring metal from the mixer th erem, and transferring. it from said elec-' tricfurnacesto a mixing ladle where. it'undergoesfurther refinement and the finalproduct is maintained substantially uniform.

3. In the manufacture of steel the method which. consists in blowing iron in basic converters, transferringit therefrom to a non acid mixer, maintaining a 'supply said' mixer, transferringImetal from said mixerto. acid "electric furnaces and refining; it-

to ac1d-'electric., furnaces. and refining it therein, transferring it' from-'said electric furnaces .to a mixing ladle where-it undergoesfurther refinement and the final roduct is maintained substantially uni Orin,

pouring the metal' fromsaid mixingladle into the casting ladles and. thence casting itinto molds.

4. In the manufacture of steel theniethod which consists in blowing iron in basic con-" i verters, thereafter refining the blown metal in acid electric furnaces and transferring it from saidelectricfurnaces tea-mixing ladle 'whereit undergoes further refinement andthe final product .is maintained uniform.

5. In the manufacture of -steel the method which consists in refining it in electric furnaces and transferring it from said furnaces-to a mixer where itundergoes fur ther refinement and elimination of -,microscopic slag and. the ,final'product is maintained substantially uniform-in carbon. 6. In the manufacture of steel the method naces and transferring it from said furnaces to a ladle where it undergoes further refinement and elimination of. mi-

croscopic slag and the final product is main 5 which consists in refining it-m electric furtained substantially uniform in carbon, andpouring the metal from said'mixing ladle to cast-mg ladles and thence casting it into s.

7. In the manufacture of steel themethodwhich consists in. refining it in electric fur ,nacesand heating it toa high (is ee,'trans'- ferring it from said furnaces "w ile highly heated to a mixer and removing-portlons only 'of the molten metal from said- Inixer", 1

from time to time and replenishing it from said furnaces so as to maintain in the mixer a. quantity of metal at least as great as that in one of said furnaces and so as to hold such quantity in the mixer long enough to effect a further refinement and elimination of microscopic slag by reason of its high temperature and quiescent condition. 8. The method of making steel consisting in forming steel in a combustion furnace orfurnaces, removing the steel to and treating it in a. series of electric furnaces, transferring the steel from the electric furnaces to a. mixer, mixing'the steel therein, and taking the steel from said mixer to the molds.

9. In the manufacture of steel the steps consisting in treating-steel in a series of electric finishing furnaces, tapping the steel therefrom into a portable mixer, maintaining a constant pool of steel in said mixer, and tapping steel therefrom at separated intervals while maintaining the pool therein.

10. In the manufacture of steel, the steps consisting of making steel in a combustion furnace or furnaces transferring the steel therefrom to a mixer and mixing it therein, taking portions of said mixed steel to and treating them in a series of electric furnaces, transferring the metal from the electric furnaces to a mixer ormixers, and mixing the refined steel therein.

11. In the'manufactu're of steel, the steps consisting of blowing molten pig iron in a basic converter and subsequently transferima es serles of electric furnaces having a nonbasic lining.

13. In the manufactureof steel, the steps consisting of blowing iron in basic convert- -ers, transferring the metal therefrom to a mixer, maintaining a pool of steel therein, taking portions of steel from said'mixer, and supplying them to and treating them in a series of electric furnaces'having a non basic lining and transferring the metal from the electric furnaces to a mixer. v 14. The method which consists in refining steel in electric furnaces, maintaining continuously a supply of molten metal for'said furnaces and a second supply in wh ch-the refined metal from said furnaces is received, so as to reduce to a minimum the periods during which said furnaces are not operat- In witness whereof, I "have hereunto signedmy name in the presence of two'sub- I scribing witnesses.

i I WILLIAM Rf WALKER. Witnesses: J. H. GEwE'oKE, D. ANTHONY Usm 

